From lojbab@access.digex.net  Sat Mar  6 22:45:13 2010
Date: Tue May 23 03:11:53 1995
From: Bob LeChevalier <lojbab@access.digex.net>
Subject:      {mluni} (was Re: TEXT: le gunse ku joi le lorxu)
To: Dylan Thurston <dpt@abel.MATH.HARVARD.EDU>
X-From-Space-Date: Tue May 23 03:11:53 1995
X-From-Space-Address: lojbab@access.digex.net
Message-ID: <LqQp9c-2sxD.A.i2E.5t0kLB@chain.digitalkingdom.org>

Dylan wrote:
>Well, I'd like to take it seriously.  Consider the following gismu:
>
>mluni [lun]
>x1 is a satellite/moon orbiting x2 with characteristics x3, orbital
>parameters x4
>
>lunra [lur]
>x1 is Earth's moon (default); x1 is a major natural satellite/moon of
>planet x2
>
>plini [ ]
>x1 is a planet revolving around x2 with planetary characteristics x3,
>orbital parameters x4
>
>First of all, the place structures are inconsistent, so something should
>definitely be changed.

Only inconsistent if they are all supposed to match. lunra does not fit
in with the other two, and hence should not be compared as to place
structure.  Instead, compare it to "terdi":

<x1 is the Earth/the home planet of race x2; (adjective:)  x1 is
<terrestrial/earthbound

and "solri"

<x1 is the sun of home planet x2 (default Earth) of race x3; (adjective:)
<x1 is solar

mluni/plini are intended to be the basis for astronomical terms, with
plini restricted to those satellites that might be of planetary nature
(which also means that they are primaries of a star; mluni need not be
primaries, nor natural, but they could be either).  I think mluni is
also more applicable to metaphor than plini.  In particular, I do not
think mluni is limited to ballistic trajectory satellites.  The nature
of the x3 and x4 for should be specific to the satellite - one being
parameters of the object itself, the other of its motion, where such
parameters are whichever of those that are essential to the context in
regards to x1 fitting into the predicate concept of a satellite.

>The difference between a {mluni} and a {lunra}, as strictly interpreted,
>seems to be that a {mluni} could include an artificial sattelite; and
>the difference between {lunra} and {plini} is primarily one of size:  a
>{lunra} is a {cmaplini} (modulo place structure).

On the contrary, solri, terdi, and lunra have definitions extended from
the specific referents "Sun", "Earth", and "Moon" to allow for those
concepts to apply to science fiction or alien cultural concepts that
correspond.  All 3 are defined with reference to a "home planet", though
lunra does not explicitly use the word "home" because in science
fictional contexts, moons of other planets in the home solar system
are often used as colonial bases.

There is a large contingent of SF fans in the Lojban community, and the
definitions were worded this way a long time ago in response to "how to
say it" questions of a science fictional nature.

>I think I see why {plini} has a place for "planetary characteristics"; so
>you could say, e.g., {le fi le xunre ku plini} to mean Mars.  But again,
>this could be done with a relative clause, {le plini poi xunre}, or a
>tanru, {le xunre plini}, or a lujvo, {le xunplini}.  I'd nominate that
>that place be removed.

You can do a lot of things with a relative clause.  The point is to
include any parameters (le ka properties) that justify defining x1 as a
"planet".  If you want to call a comet a plini, or an asteroid, or the
earth's moon, you are constraining the definition of plini from the
traditional cultural one for a planet, and the value for x3 should
contain that information that makes the claim of planethood true.
"Parameters" is thus a somewhat more flexible way to say "standard",
because I don't think that a specific standard as opposed to a set of
properties will be the most frequent value (should anyone ever decide to
specify the value %^).

>I'd also nominate that {mluni} not be restricted to astronomical
>bodies--that seems like an artificial restriction that's not necessary.

There is no such restriction in the definition.  I gave an example in
another post of how mluni might apply to specific orbiting of a stove.

>And I'd also nominate that "orbital characteristics" be changed to
>"route" to confuse people less.  Even for astronomical use, I think
>that's fine.  (Though it might make saying something like
>"geosynchronous sattelite" somewhat more difficult.)

Exactly.  So use a route if that is more convenient, or a property
abstract "le ka stodi sraji galtu lo pa stizu" if that is a better style
of specifying the satellite's motion.

>The restriction to ballistic flight is an interesting idea--then one
>could say {le bolci le stedu cu mluni}, but not {le lorxu cu mluni le
>toknu}.  I don't know where I stand on that.

We have words for ballistic trajectory objects - danti and farlu.

lojbab